Over medium heat, in a saucepan, boil the water and 2 tablespoons sugar together.
When the sugar has melted, add the coconut milk. Simmer for 10 minutes or until slightly thick.
Transfer the coconut mixture to a container that can be sealed with a cover then let it reach room temperature.
Put the container in the freezer overnight or until it freezes. Move around the granita with a spoon every hour. If the granita solidifies into one compact hard piece because you were not able to move it around, just break some pieces and put them in a blender to break them up right before serving.
To prepare the mango sauce, put the mango pulp, 1 tablespoon sugar, lime juice, and zest in a blender and blend until smooth. Refrigerate.